Vacuum Pumps Overview

The standard DIN 28400 Part 2 provides an overview of commonly used vacuum pump types. 

However, in the area of chemical process engineering only pumps of the following general types are used  

The areas of application for these vacuum pumps are all within the rough and medium vacuum range, the principal vacuum range for chemistry processes. Only the short path and molecular distillation processes rely also high-vacuum pumps like the diffusion pump or even the turbomolecular pump (kinetic gas pumps). High-vacuum pumps are not covered in this book. For these refer to [2, 3]. 

It is the task of all vacuum pumps outlined above to generate a vacuum in a process engineering plant, for example, and to provide enough pumping speed. A pumping speed is in the end only a volume which passes per unit of time through an area. 

---

GC-MS is the most widely used hyphenated technique and there have been many comprehensive reviews. This description will only be a brief overview and touch on specific issues relevant to the coupling of the GC to the MS. The interfacing of the GC outlet to the MS inlet usually requires some type of selective carrier gas removal. Although direct connection of the GC to the MS is feasible (if large enough vacuum pumps are used), this is rarely done. This is because the vacuum at the outlet of the column can affect the separation efficiency, making most calculations of column retention parameter or efficiency calculations impossible, and the MS... 

Rectification fractionates feed mixtures consisting of two or more components into two or more product streams. These streams include and are often limited to an overhead distillate stream and a bottoms stream, whose compositions differ from that of the feed stream. From the distillate stream, a specific portion called reflux is usually pumped back to the column to increase the product purity. Figure 16.1 provides an overview about the process streams and summarises the main apparatus as well as the peripheral and internal equipment involved in a packed vacuum rectification column. 

---